Immunosupressive agents used to treat a wide range of autoimmune diseases carry similar risks of serious infections during pregnancy, according to a large population based study in The BMJ.
The observational study involving almost 5,000 pregnant women with lupus, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and inflammatory bowel disease found no statistically significant differences in the risk of serious infections (defined as hospital admission for bacterial or opportunistic infection) with steroids, non-biologics and TNF inhibitors.
According to the analysis carried out by Rishi J Desai from the Brigham and Women’s Hospital in Boston and colleagues the crude incidence rates of serious infections per 100 person years among 2598 steroid users, 1587 non-biologic immunosuppressant users, and 776 TNF inhibitors users were 3.4 (95% confidence interval 2.5 to 4.7), 2.3 (1.5 to 3.5), and 1.5 (0.7 to 3.0), respectively.
The authors said that while it was possible the finding with TNF inhibitors could be due to insufficient statistical power to detect a small effect size, it did allow the possibility of a large increase in risk of serious infection with the agents to be ruled out.
“Based on the upper bounds of our 95% confidence intervals…we can exclude the possibility of the risk of serious infections being higher than approximately twofold to fourfold with TNF inhibitors compared with other treatment options (upper confidence limit 2.26 and 3.93 versus steroids and non-biologics, respectively” they wrote.
However, they noted that evidence for the safety of TNF inhibitor use in pregnancy was limited.
“Although some early reassuring data have been reported regarding their teratogenic potential more research is required to confirm these observations,” they said.
The analysis also revealed that high-dose steroids during pregnancy were an independent risk factor for serious infections (coefficient for each unit increase in average prednisone equivalent mg daily dose=0.019, P=0.02).
However, they noted that the absolute risk of serious infection remained low with low doses of steroids (0.014 to 0.017 at <10mg average daily doses).
“Low steroid doses with appropriate monitoring may provide a favourable risk-benefit balance for the management of acute flares,” they suggested.
They concluded that the selection of an appropriate course of immunosuppressive treatment for managing active autoimmune conditions in pregnancy was a complex task that needed to consider both maternal and fetal outcomes.